Combined evaporator and feed-water heating system



sepf.23,1924. 1,509,634

vs BRowN COMBINED EVAPORATOR AND WATER HEATING SYSTEM Filed Jan. 26.1920

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STANLEY BEtW'N, 01@ GARDEN GETS?, NEWLY YORK, ASSIGNOR T@ TEE 'GRISCOM RUS- SELL GlllllL/lli, F NEW YUR, lll'. Y., A CRPORATXN @l GMBNED EVA'PURATQE AND FEED-WATER HEATN'G SYSEll-slllll.

Application lerl January 26, 1920?. Serial No. $253,998.

To @ZZ whom may concern.

Be it lniovvn that l., Smarter Bizovvn., a citizen ot the United States, residino' at Garden City, in the county of Nassau, ,State o'i New Tlorla have invented certain new and useful improvements in Combined ldvaporator and lF'e-ed-lll/'ater lileating7 Systems; and do hereinT declare the `following to be a full, clear, and enact description otl returns from which are a condensate Toit lovvl pressure and low temperature Well below the atmospheric boilingpoint of 212 degrees l1". ln many establishments the quantity oli low temperature condensate is not'over 85% of the total requirements for the boiler .teeth due to various losses in auxiliam7 apparatus, and the use of the main boiler steam tor various industrial purposes. rl`his dei'icit is supplied bv the evaporation olf impure Water in evaporators utilizing steam 'from the main boilers as the heating fluid. and in order 'for the plant to be economically run is necessar;T that the heat thus diverted 'trom the main boiler to the evapo rators be 'returned to the system in the con densed steam used in the evaporator an d the vapor 'from the evaporators, and it has heretofore been the custom to utilize the con-- densed steain and vapor -trom the evaporators in' reed water heaters tor both the evaporator leed and the main' boiler condensed steam and vapor from all sources beinp; returned to a large open heater from which the boiler feed is pumped.

istne purpose ol the present invenw tion to provide a plant or this general char acter in which the heat 'from the evaporator plant shall be returned to the sjvstein as or as possible in the boiler :ieed heater, allovvia@L more expensive condens necessary tor feed Water heaters to be ot low cost and small capacity.

ln the accompanying7 drawinga l have illustrated diagrammaticallv a vtypical power plant arrangement embodying my invention. y'Referring to the drawing., l and 2 indicate the tivo effects ot a typical evaporator plant to which the ravv Water to be evapo rated is fed through a teed pipe 3 and the heating' fluid or steam from the main boilers is ted from the steam main b v n pipe l to the coils of the lirst effectni" the evaporator. r1l`he vapor iirom the" lirst eiiect passes through the vapor line 5 to the coils ot the second effect and the condensate from the coils is discharged/through the usual trapsl to a common Adischarge line (i.

The vapor from the second effect is discharged through the vapor line 8 to the 'leed .heater 7 which serves as a. condenser for the vapor7 the condensate Jfrom which` is piped through the main return line 9 to the plant heater l0, a suitable trap being interposed in the line to prevent the discharge oli vapor to the heater. -Water pumped 'from the heater l0 through the heater 7 takes up the heat from the vapors which enter the said heater 7.

The feed heater 7 is at a lower pressure than the drains in the line 6 from the coils ot the heat 'from the drain line may be used in the feed heater bv providing a trap Q0 densed in the leed water heater in the mann @l ner described in mv copendmg application Serial lio. 353.999 tiled concurrently 'with which has matured into -Patein'; ,l.l0`.-

lllxlleceinber E20. 192i. A valve llil is preferably provided in the riser 'il so Y all ot the coil drains may be forced to into the boiler leed heater l0 if desiredrse boileniieed heater r .ceives the exhaust steam "from the various auxiliary apparatus oi" 'theI plant and also the temperature condensate, "from the engines oli the main power plant'through the pipe l2, this con-4 densate being1 normalhv at a coinparativelji' temperature ot about 864.00 degrees perature in the plant heater may be considerably below 212 degrees F., at which teinperature it may with perfect safety be maintained. In order to maintain the heater 10 at 212 degrees under such circumstances .so that the auxiliary feedwater heater 7 may be kept of as small size as possible, I may*L draw oiipart of the vapor from the vapor line 8 through a pipe 13 directly to the open heater, and provide a valve in the pipe 13 for checking the flow of vapor through the pipe 13, when the temperature inthe boilerfeed heater 10 rises above boiling point.

For the purpose of illustration I have shown an ordinary automatic back pressure valve-141 having a diaphragm chamber 15 connected to the heater 10 through a pilot pipe `16, the lvalve being set to cut ofi' the flow o f vapor through the pipe 13 upon the development of any pressure'in theheater. As the pressure in the heater is normally conlsiderably less than that in the feed water condenser, the vaporwill flow in the-pipe 13'to the full capacity of the back pressure th 7 valve and consequently willl always tend to maintain the heater 10' at the highest temperature (and corresponding pressure) for which the valve is set.

The inventionof this application is particularly useful where there is a' changing load on the power plant `which produces variations in the' relativey quantity of vapor and auxiliary steam to be condensed and the condensate from the main engines. 4For instance, in central stations the boiler makeup required and the auxiliary steam used is comparatively constant while ythe load onl the main engines varies greatly. By the arrangement here shown the boiler feed heater 10 will be prevented from receiving a supply of steam in-A excess of that required to maintain it in operation at its maximiuin pressure and temperature conditions, inasmuch as the heat contained inthe auxiliary steam will not ordinarilyy be excessive. In case the heat returns to the heater 10.are deficient, the regulating valve 14 will serve to adm itadditional steam to the open heater and tend to maintain it in operation at the proper temperature. If any regulating means are provided for controlling the quantities. of vapor delivered to the heater 1() the plant has to be designed so that under the conditions of peration when the quantity of vapor and steam. to be condensed is greatest in proportion 'to the quantity of low temperature condensate the boiler-feed .heater will not be raised above atmospheric boiling point. Hence, at normal load condi-v tions the heater 10 will be at an unnecessarily low temperature.

' It is desirable to maintain the temperature of the boilerfeed heater 10 at about the atmospheric boiling point for two further reasons. First, the turbine condensate, and in some cases'tqhe condensed evaporator vapor, contain entrained gases. These gases are .much better relieved at 212 degrees than at lower temperatures. In the second place, the surface condensers employed for cor.- densing the exhaust steam from the main engines are seldom absolutely tight so that Vthere is frequently a sucking in of a small portion of the impure water used as condensing means. The impure solid content so brought in is passed to the power plant heater andthe higher the temperature of the heaterV` the better will be the cracking out, or, depositing, of such impurities.

It will of course be understood that various changes may be made in the arrangement of the apparatus. For instance, a. portion of the vapor Vfrom the line 8 may be used in a feed water heater for the evaporators; or l,a second feed water heater may be used in series with the heater 7 in the manner shown in my co-pendin application above referred to, the gist of t e present invention being e arrangement hereinafter claimed for maintaining the boiler-feed heater 10 at its maximum temperature.

I claim:

1. In a power plant system, the eombination of a boiler feed heater at relatively low pressure for receiving the returns from the steam-utilizing apparatus of an evaporator plant for making up the fiuid loss from the power plant system, means for condensing the vapor from said evaporator system comprising a condenser, the pressure in said condenser being appreciably higher than that in said boiler feed heater, a vapor line leading thereto, and a. branch from said vapor line to said heater. and means controlled by the temperature of the heater for regulating the quantity of vapor delivered through said branch line for maintaining said heater at a predetermined temperature.

2. In a power plant system, the combination of a boiler feed heater for receiving the returns from the steam-utilizing apparatus of an evaporator plant for makingr up the fluid loss from the power plant` system, means for condensing the vapor from said evaporator system comprising'a second feed water heater maintained at a pressure appreciablyabove that of said boiler feedv heater for heating the water from said heater, a vapor line leading to the vapor space of said second heater, and a branch iroaeea.

. from said vapor line to said boiler-feed and means for conserving the heat in the heater, and means controlled by the temperature of said heater for regulating the quantity of vapor delivered through said branch line forl maintaining said heater at a predetermined temperature.'

3. In a power plant system, the combination of a boiler feed heater for receiving the return from the steam-utilizing apparatus, an evaporator system for making up the liquid losses from said power system,

discharge from said evaporator comprising a sc'cond feed water heater maintained above atmospheric pressure for heating the water fromsaidzboiler feed heater, a vapor line from said evaporator to. the vapor space of said second heater, a branch from s aid vapor line to the boiler feed heater, and an automatically operating valve in said branch line and aregulator therefor controlled bythe temperature of said boiler feed heater to maintain the temperature of Athe heater at approximately atmospheric `boilirg temperature. y 4. n an evaporator system, means for condensing the vapor therefor' comprising a condenser m-aintainted at a pressure above `atmospheric and a boiler feedl heater, an

automatically actuated regulator adapted to admit to'said heater suliicient steam to means for regulating the liowV of vapor through said branch comprising a valve, and a regulator therefor controlled by the temperature of the liquid in the heater and adapted to admit to said heater sufficient steam to maintain the temperature of said heater at approximately atmospheric vboiling point and cause the remainder of the steam from said evaporator system to flow into said condenser.

6. lin a power plant system, the combination of a boiler feed heater for receiving the .condensed returns from steam utilizing apparatus and also for receiving uncondensed steam or vapor from such apparatus, a condenser forl'conden'sing a portion 'of such steam or vapor, a by-pass around the condenserfrom the vapor line to the heater and a valve in said by-pass controlled by the temperature of the heater for admitting to said heater a quantity of steam sufficient to-mainta-in' the temperature of said heater at approximatelyy atfniospheric boiling point.

7. ln a system of the class described, a boiler feed heaterfor receiving the returns `from the steam utilizing apparatus, evap- 'orators for supplying purified water to said system, a condenser maintained at ""elatively high pressure through which water from said boiler feed heater is passed before admission to vthe boiler, a vapor line from said evaporators to said condenser, whereby the vapor output of said evaporators is condensed and the latent heat ofthe vapor iinparted to the boiler feed water, means for i conveying condensate from said condenser into said boiler feed heater, and means for admitting the discharge from the heating elements of said evaporators to saidheater..V '8. In a system of the class described, a

boiler feed heater for receiving the returns from the steam utilizing apparatus, evaporators for supplying purified water to said system, a condenser maintained at relatively high pressure'through which water from .sa-id boiler feed heater is passed before admissionto the boiler, a vapor line from said evaporators to' said condenser, whereby thevapor output of said evaporators is con- "densed and the latent heat of the vapor imparted to the boiler feed water, and means for transmitting to the boiler feed Water the contained heat 1n the drains from said condenser and in the dischargefrom the heating elements of said evaporators. I

9. In a'system of the class-described, a boiler` feed heater for receivingthe returns from the steam utilizing apparatus, evaporators for supplying purified Water to said system, a condenser maintained at relatively high pressure through which Water from said boiler feed heater is passed'before admission to the boiler, a vapor line from said evaporators to said condensers whereby the vapor output of said evapora/ters is condensed and the latent heat of'. thev vapor imparted to the boiler feed/water, means for subjecting the drains/from. the heating elements of. said evaporators to a reduced pressure, whereby a portion of said drains vwill be vaporized by reason of their` contained heat, means for conducting the vapor thus Aformed into said condenser, means for conveying the liquid portion of said drains into the boiler feed heater, and means for conveying condensate from said condenser into said heater.

In testimony whereof li ax my si nature..l

STANLEY BR 

